Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Vela [1] |
Right ascension | 10h 06m 07.21043s [2] |
Declination | −52° 11′ 16.5788″ [2] |
Apparent magnitude (V) | 6.499±0.009 [3] |
Characteristics | |
Evolutionary stage | Red clump [4] |
Spectral type | K1III [5] |
B−V color index | 0.986 [3] |
Astrometry | |
Radial velocity (Rv) | 4.7±0.4 [6] km/s |
Proper motion (μ) | RA: −55.682 mas/yr [2] Dec.: +16.413 mas/yr [2] |
Parallax (π) | 7.4825±0.0196 mas [2] |
Distance | 436 ± 1 ly (133.6 ± 0.4 pc) |
Absolute magnitude (MV) | +0.876±0.013 [3] |
Details [3] | |
Mass | 2.41±0.10 M☉ |
Radius | 9.0±0.2 R☉ |
Luminosity | 45±1 L☉ |
Surface gravity (log g) | 2.860±0.096 cgs |
Temperature | 4,989±46 K |
Metallicity [Fe/H] | +0.139±0.035 dex |
Other designations | |
R Vel (obsolete), CD−51°4471, HD 87816, HIP 49477, HR 3978, TYC 8194-294-1 [7] | |
Database references | |
SIMBAD | data |
HD 87816 is a star in the constellation Vela. With an apparent magnitude of 6.499, [3] it is very close to the average threshold for naked eye visibility, and can only be viewed from sufficiently dark skies, far from light pollution. [8] Based on parallax measurements, it lies at a distance of 436 light-years. [2] It is moving away from the Solar System at a velocity of 4.7 km/s. [6]
The spectrum of this star matches a spectral class of K1III, [5] with the luminosity class III indicating it is a giant star that has exhausted the hydrogen at its core. It is now fusing helium, being in the evolutionary stage known as the horizontal branch. [4] The star has 2.4 times the Sun's mass, having grown to a radius 9.0 times the radius of the Sun. It shines with 45 times the Sun's luminosity at an effective temperature of 4,989 K. [3] The temperature gives it the orange hue typical of K-type stars. [9]
HD 87816 was once believed to be a variable star and received the variable-star designation R Velorum, but it is now considered a constant star. [1]
HD 87816 hosts two known exoplanets, discovered in 2025 via Doppler spectroscopy. Both are gas giants, like Jupiter and Saturn. [10]
Planet b has a minimum mass of 6.7 Jupiter masses (MJ). It takes 484 days (1.33 years) to complete an orbit around HD 87816 and has a very high orbital eccentricity of 0.78, among the highest of exoplanets orbiting giant stars. [10]
Planet c has a minimum mass of 12.2 Jupiter masses. It takes 7,600 days (21 years) to complete an orbit around its host, and has a low eccentricity of 0.11. [10]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (years) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥6.74±0.13 MJ | 1.618±0.0003 | 1.3256+0.00036 −0.00033 | 0.780±0.005 | — | — |
c | ≥12.20+2.15 −1.59 MJ | 10.14+0.99 −0.48 | 20.80+3.1 −1.46 | 0.19±0.07 | — | — |